System and method for a demand driven lean production control system

ABSTRACT

A system is disclosed providing visualization of a production control framework. The system includes a database storing production control data associated with one or more entities and a production control system coupled with the database and configured to model a production control framework of the one or more entities. The production control system includes one or more work centers authorizing one or more tasks for one or more parts and one or more manufacturing processes that produce one or more finished parts using the one or more parts.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/563,348, filed on 23 Sep. 2009 and entitled “System and Method for aDemand Driven Lean Production Control System,” which claims the benefitunder 35 U.S.C. §119(e) of U.S. Provisional Application Ser. No.61/100,713, filed 27 Sep. 2008, entitled “DMK: An Advanced Demand DrivenLean Production Control System.” U.S. patent application Ser. No.12/563,348 and U.S. Provisional Application Ser. No. 61/100,713 arecommonly assigned to the assignee of the present application. Thedisclosure of related U.S. patent application Ser. No. 12/563,348 andU.S. Provisional Application Ser. No. 61/100,713 are hereby incorporatedby reference into the present disclosure as if fully set forth herein.

TECHNICAL FIELD OF THE INVENTION

This invention relates generally to production control systems, and moreparticularly to a system and method for a demand driven lean productioncontrol system.

BACKGROUND OF THE INVENTION

In a traditional lean manufacturing environment, a kanban card system(e.g., a physical card) is used as a means to control the productionflow on a manufacturing floor. The kanban card system is typicallyreferred to as a pull signal, because the kanban card is attached to acontainer of parts which travels around the manufacturing floor. Whenthe container is empty, the empty container and the kanban card arriveback at a production resource to refill the container, as componentsupplies and manufacturing capacity permit.

In an effort to overcome the above-discussed deficiencies, amanufacturing entity is required to hold higher or excessiveinventories. However, increasing inventory without a forward lookingmechanism is unresponsive to real-time demand. In addition, because thekanban card system is backward looking a manufacturing entity isinherently exposed to constraints and bottlenecks on the manufacturingfloor. This inability to provide a forward looking production controlmechanism is undesirable.

SUMMARY OF THE INVENTION

A system providing visualization of a production control framework isdisclosed. The system includes a database storing production controldata associated with one or more entities and a production controlsystem coupled with the database and configured to model a productioncontrol framework of the one or more entities. The production controlsystem includes one or more work centers authorizing one or more tasksfor one or more parts and one or more manufacturing processes thatproduce one or more finished parts using the one or more parts.

A method providing visualization of a production control framework isdisclosed. The method provides for storing production control dataassociated with one or more entities in a database. The method furtherprovides for authorizing one or more tasks for one or more parts at oneor more work centers and producing one or more finished parts using theone or more parts at one or more manufacturing processes.

A computer-readable medium embodied with software enabling visualizationof a production control framework is disclosed. The software isconfigured to store production control data associated with one or moreentities in a database. The software is further configured to authorizeone or more tasks for one or more parts at one or more work centers andproduce one or more finished parts using the one or more parts at one ormore manufacturing processes

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the invention are setforth in the appended claims. However, the invention itself, as well asa preferred mode of use, and further objectives and advantages thereof,will best be understood by reference to the following detaileddescription when read in conjunction with the accompanying drawings,wherein:

FIG. 1 illustrates an exemplary supply chain network according to apreferred embodiment;

FIG. 2 illustrates the production control system of FIG. 1;

FIG. 3 illustrates an exemplary model of production environment of anentity of FIG. 1;

FIG. 4 illustrates an operator dashboard interface provided at each workcenter of FIG. 3;

FIG. 5 illustrates an exemplary method for performing a CONWIPassignment workflow;

FIG. 6 illustrates an exemplary method for providing production controlauthorization signals in the production environment of the entity ofFIG. 1; and

FIG. 7 illustrates an exemplary method for providing production controlsignals in the production environment of the entity of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made to the following detailed description of thepreferred and alternate embodiments. Those skilled in the art willrecognize that the present invention provides many inventive conceptsand novel features, that are merely illustrative, and are not to beconstrued as restrictive. Accordingly, the specific embodimentsdiscussed herein are given by way of example and do not limit the scopeof the present invention.

FIG. 1 illustrates an exemplary supply chain network 100 according to apreferred embodiment. Supply chain network 100 comprises a productioncontrol system 110, one or more entities 120 a-120 n, one or morecustomers 130 a-130 n, a network 140, and communication links 142, 144a-144 n and 146 a-146 n. Although a single production control system110, one or more entities 120 a-120 n, and one or more customers 130a-130 n, are shown and described, embodiments contemplate any number ofproduction control systems 110, any number of entities 120 a-120 nand/or any number of customers 130 a-130 n, according to particularneeds. In addition, or as an alternative, one or more other entities 120a-120 n may be, for example, manufacturing entities, manufacturingprocesses, production facilities, and other like entities. In addition,production control system 110 may be integral to or separate from thehardware and/or software of any one of one or more entities 120 a-120 n.

In one embodiment, supply chain network 100 models a production controltechnique for, items, products, parts, materials, goods, and/or servicesthrough one or more entities 120 a-120 n based on demand received fromone or more other entities 120 a-120 n and/or one or more customers 130a-130 n. As described below in more detail, production control system110 utilizes three types of production control authorizations: DTagproduction control signals, MTag production control signals and kanbanproduction control signals (i.e., authorizing pull-based production of astandard pack (i.e., incremental (smallest) production quantity of anitem). In one embodiment, a DTag production control signal is a demandauthorization introduced into production control system 110 via a BOMexplosion for all produced parts required to satisfy a demand wheneverthat demand is introduced into the production control system 110. Forexample, the demand may come from a pacemaker operation, and/or, foritems that are not scheduled on pacemaker operations, directly fromeither one or more customers 130 a-130 n or an increase of one or morefinished good target inventories.

In another embodiment, an MTag production control signal is either workcenter-specific or non-work center-specific (a work center set of one ormore production resources, indistinguishable and acting as one forplanning purposes). The number of work center-specific MTags, defined ata work center-pair level and specifying both a consuming work center anda producing work center, represents the maximum amount of inventorypresent at a destination work center which was produced at a particularsource (producing) work center. In addition, the non-workcenter-specific MTags are required for production of any part consumingraw material. In an embodiment, the number of MTags and kanban presentin production control system 110 may be fixed at a predetermined levelto achieve optimal product flow and inventory levels within one or moreentities 120 a-120 n. In addition, the number of MTags and kanban foreach part represents the maximum amount of inventory present in thesystem for that particular part at a specific time period.

In one embodiment, supply chain network 100 may operate on one or morecomputers that may be integral to, or separate from, the hardware and/orsoftware that support production control system 110, one or moreentities 120 a-120 n, and one or more customers 130 a-130 n. These oneor more computers may include any suitable input device, such as akeypad, mouse, touch screen, microphone, or other device to inputinformation. In addition, these one or more computers may include anysuitable output device that may convey information associated with theoperation of supply chain network 100, including digital or analog data,visual information, or audio information. Furthermore, these one or morecomputers may include fixed or removable computer-readable storagemedia, such as magnetic computer disks, CD-ROM, or other suitable mediato receive output from and provide input to supply chain network 100. Inaddition, these one or more computers may include one or more processorsand associated memory to execute instructions and manipulate informationaccording to the operation of supply chain network 100.

In addition, or as an alternative, production control system 110, one ormore entities 120 a-120 n, and/or one or more customers 130 a-130 n mayeach operate on one or more separate computers or may operate on one ormore shared computers. Each of these one or more computers may be a workstation, personal computer (PC), network computer, personal digitalassistant (PDA), wireless data port, or any other suitable computingdevice. In another embodiment, one or more users may be associated withone or more entities 120 a-120 n and/or one or more customers 130 a-130n. These one or more users may include, for example, “planners,”“operators,” and/or “plant managers” handling production controlsystems, requirements, procedures and policies within supply chainnetwork 100. In addition, or as an alternative, these one or more usersmay include, for example, one or more computers programmed toautonomously handle production control systems, requirements, proceduresand policies within supply chain network 100.

In one embodiment, production control system 110 may be coupled withnetwork 140 using communications link 142, which may be any wireline,wireless, or other link suitable to support data communications betweenproduction control system 110 and network 140 during operation of supplychain network 100. One or more entities 120 a-120 n may be coupled withnetwork 140 using communications link 144 a-144 n, which may be anywireline, wireless, or other link suitable to support datacommunications between one or more entities 120 a-120 n and network 140during operation of supply chain network 100. One or more customers 130a-130 n may be coupled with network 140 using communications links 146a-146 n, which may be any wireline, wireless, or other link suitable tosupport data communications between one or more customers 130 a-130 nand network 140 during operation of supply chain network 100.

Although communication links 142, 144 a-144 n and 146 a-146 n are shownas generally coupling production control system 110, one or moreentities 120 a-120 n, and one or more customers 130 a-130 n to network140, production control system 110, one or more entities 120 a-120 n,and one or more customers 130 a-130 n may communicate directly with eachother, according to particular needs. In addition, or as an alternative,production control system 110 may reside within one or more entities 120a-120 n and/or one or more customers 130 a-130 n, according toparticular needs.

In another embodiment, network 140 may include the Internet and anyappropriate local area networks (LANs), metropolitan area networks(MANS), or wide area networks (WANs) coupling production control system110, one or more entities 120 a-120 n, and one or more customers 130a-130 n. Those skilled in the art will recognize that the completestructure and operation of communication network 140 and othercomponents within supply chain network 100 are not depicted ordescribed. Embodiments may be employed in conjunction with knowncommunications networks and other components.

FIG. 2 illustrates production control system 110 of FIG. 1 in greaterdetail in accordance with the preferred embodiment. As discussed above,production control system 110 comprises one or more computers at one ormore locations including associated input devices, output devices,computer-readable storage media, processors, memory, or other componentsfor receiving, processing, storing, and communicating informationaccording to the operation of supply chain network 100. In oneembodiment, production control system 110 stores production control dataassociated with one or more entities 120 a-120 n and/or one or morecustomers 130 a-130 n, in database 220.

Server 210 comprises one or more engines 212, including a demandpropagation engine. In addition, although server 210 is shown anddescribed as comprising one or more engines 212, embodiments contemplateany suitable engine or combination of engines, according to particularneeds. Database 220 comprises one or more databases or other datastorage arrangements at one or more locations, local to, or remote from,server 210. Database 220 includes, for example, one or more data modules222. As an example only and not by way of limitation, production controlsystem 110 stores production control data associated with one or moreentities 120 a-120 n and one or more customers 130 a-130 n that may beused by server 210, and in particular, by one or more engines 212.

FIG. 3 illustrates an exemplary model of production environment ofentity 120 a of FIG. 1 in greater detail in accordance with thepreferred embodiment. Entity 120 a comprises a plurality of work centers310 a-310 n and a plurality of manufacturing processes 320 a-320 n thatproduce one or more finished parts P_(N). Entity 120 a further comprisesa plurality of production control variables, such as, for example,output buffer of stage i (B_(i)), demand queuing stage i (D_(i)), numberof DTags in stage i (d_(i)), unique number identifying a productionstage (i,j), kanban queuing station in stage i (K_(i)), number of kanbanin stage i (k_(i)), MTag queuing station in stage i (M_(i)), MTag forproducer i and consumer j (₁m_(N)=CONstant WIP) (_(i)m_(j)),manufacturing process of stage i (MP_(i)), number of manufacturingstages (N), raw material buffer 0 feeding stage 1 (P₀), Max inventory ofBi (s_(i)), synchronization station at stage i (U_(i)). Although aplurality of work centers 310 a-310 n, a plurality of manufacturingprocesses 320 a-320 n, and a plurality of production control variablesare shown and described, embodiments contemplate any number of workcenters 310 a-310 n, any number of manufacturing processes 320 a-320 nand/or any number of production control variables, according toparticular needs.

In one embodiment, each work center 310 a-310 n consumes part P_(i−1)and produces part P_(i) wherein work center 310 a is stage 1 andconsumes raw material P₀ with, for example, infinite supply. In anotherembodiment, each buffer B_(i) has a target inventory of s_(i) which isset to the sum of capacity buffer and production lead time bufferrequirements, which “primes” the value stream with a buffer of highvolume parts to improve, for example, system responsiveness.

As an example only, and not by way of limitation, whenever a new demandis received at entity 120 a of FIG. 1 a demand kanban is generated byexploding the BOM for the demanded part and providing a demand kanbanfor each additional standard pack required of a component or finishedgood (i.e., a produced part that is shippable to one or more customers130 a-130 n) part. When a demand kanban appears at a work center it isavailable to authorize replenishment production of the item, whichbegins when an empty kanban, as well as empty MTag or CMTag, if needed,is also present and Work Center capacity permits.

In addition, the DTag production control signal provides thefunctionality of extended kanban, which is a production control policythat results in fewer full kanban (less inventory) on average in thesystem than the standard kanban enables, since standard kanban authorizereplenishment as soon as empty kanban arrive at the producing WorkCenter. The quantity of inventory required by extended kanban on averageis less than that required without extended kanban by the quantity ofinventory of the part represented by the sum of the number of kanban inthe loop size in excess of that required by the current demand signal.Therefore the DTag production control signal provides for controllingexcess production in environments where the demand volume and/or mix isvariable.

In another embodiment, the MTag production control signal is a materialauthorization signal which provides the functionality of bothPaired-cell Overlapping Loops of Cards with Authorizations (POLCA)production control policy and CONstant Work-In-Process (CONWIP)production control policy. POLCA enables management of capacityconstrained work centers. For example, POLCA production controltechniques constrain replenishment until a POLCA signal is available,which represents available capacity on a downstream work center. ThePOLCA signals are thus work center-specific, not part-specific, andspecify a consuming (generally bottleneck) work center and a producingwork center supplying parts to the consuming work center. When theconsuming work center is ready to accept more work, which is generallyas parts produced at the consuming work center are released to finishedgood or downstream processes, POLCA signals are released to eachproducing work center for each standard pack of component partsrequired. When a POLCA signal appears at the producing work center it isavailable to authorize replenishment production of component itemsproduced at that work center. In the present invention the MTag signalacts just like the POLCA signal. When MTags are used in conjunction withkanban, replenishment begins when sufficient empty kanban, MTags, andany other required production control signals (such as DTags and/orCMTags) are also present at the producing work center and work centercapacity permits. This production control policy results in more emptykanban (less inventory) for the component part on average in theproduction control system. The MTag, as in POLCA, thus provides forlimiting excess inventory in front of, for example, a bottleneck workcenter.

As discussed above, the other production control policy enabled by thepresent invention is CONWIP, which is enabled by a special form of theMTag, the CMTag. The CONWIP production control policy is similar toPOLCA in that it provides a constraint that is not part-specific. TheCONWIP authorization signal, the CMTag in the present invention, isneither part-specific nor work center-specific; it is instead sitespecific. The purpose of the CMTag is to limit the total amount of WIPthroughout the production control system (hence the name CONstant WIP).The CMTag provides an additional constraint on production at one or morestage 1 work centers, which work centers generally consume only raw orprocured materials. The stage 1 work centers are generally the mostupstream work centers in the value stream (supply chain network), andwhich produce components required in most or all finished good itemsproduced at the site. At such a stage 1 work center, a CMTag is neededfor every part produced at that work center, so production may onlybegin when the number of CMTags available at the work center is thestandard pack quantity times the trigger quantity. Once a standard packis completed, a CMTag is assigned to each unit of material in thestandard pack. Each CMTag travels with its assigned component throughoutthe value stream and is only released back to stage 1 work centers toauthorize further production when the finished good comprising the unitof material to which the CMTag is assigned is shipped to one or morecustomers 130 a-130 n. At that time the CMTag is released and madeavailable to another initial production work center as appropriate.

In one embodiment, if the number of units of stage 1 parts perintermediate or finished good item is large, the number of CMTags in thesystem may become quite large, and may be bulky or awkward when, forexample, physical cards are used to implement CONWIP controls. Tomitigate this problem, embodiments provide for selecting a subset of theparts produced at stage 1 work centers for CMTag authorization, ratherthan all stage 1 produced parts, may be sufficient. If there is a singlestage 1 produced part that appears in all finished good items in arelatively constant proportion per finished good item, then enablingCMTag authorization for that one part has much the same effect on thesystem as enabling CMTag authorization for all stage 1 parts. However,if the distribution of this part is such that there are more units ofthe part in some finished good items than others, then enabling CMTagauthorization for only this part will allow more finished goodsinventory of items that consume less of the part, and less finishedgoods inventory of those items that consume more of the part. If this isinappropriate, than a subset of parts can be identified that behave inthe desired manner, that is, when considered as a group the proportionconsumed by each finished good item is approximately the same. When thisis the case, CMTag authorization is enabled for that subset of parts,rather than for all stage 1 parts, to achieve the desired CONWIP result.In any case, selecting a subset of parts rather than all stage 1produced parts implies that production at other stage 1 work centers,not controlled by CONWIP, will not be constrained and thereforeexcessive inventories may result.

In one embodiment, the behavior of CONWIP is such that it onlyconstrains the initial operations of a value stream. That is, since aCMTag is assigned to every single unit of material for key producedparts, there will always be CMTags available for every task atdownstream operations, so these operations will not be constrained byCMTags. In addition, the CMTag loop size limits the total amount ofinventory possible in the production control system at any particulartime, and when enabled in conjunction with kanban, CMTags result infewer full kanban on average. This is particularly useful in high mixenvironments where the demand pattern may shift so frequently thatkeeping the kanban loop sizes fully aligned with the demand mix isimpractical. If, for example, the total volume of demand is relativelystable then a constant CMTag loop size can be used in addition to kanbanto allow the mix to change with demand and utilize larger kanban loopsizes without incurring the additional inventory expense necessary tomaintain responsiveness. Otherwise, when the total volume of demand isrelatively unstable, the CMTag loop size must be constantly realignedwith the demand signal in order to maintain customer service and optimalinventory levels. In addition, setting the CMTag loop size to the sum ofall of the kanban loop sizes in the system disables the CMTag constraintby making it non-constraining.

In another embodiment, the kanban production control signal supportspull-based production control on the “production floor” of one or moreentities 120 a-120 n. A kanban is a part-specific signal required toauthorize production of a standard pack of that part. The number ofkanban signals present in the production control system represents thetotal amount of inventory of the part possible in the system at any onetime.

FIG. 4 illustrates an operator dashboard interface 400 provided at eachwork center 310 a-310 n of FIG. 3. In one embodiment, operator dashboardinterface 400 comprises one or more graphical elements including jobqueue 410, production history 412, and buttons 430. Although, operatordashboard interface 400 is shown and described as having one or moregraphical elements including a visual representation of job queue 410, aplurality of tasks 411, production history 412, production controlsignal types 420 a-d, and buttons 430, embodiments contemplate anysuitable number of graphical elements, according to particular needs. Aswill be explained below in greater detail, operator dashboard interface400 provides a visual representation of a production control frameworkto, for example, determine which tasks 411 to produce, the order inwhich to produce tasks 411 and a record of when each task 411 is startedand completed for each work center 310 a-310 n.

As discussed above, production control system 110 of FIG. 2 utilizesthree types of production control authorizations, the DTag productioncontrol signal, the MTag production control signal and the kanbanproduction control signal, in order to authorize production of one ormore tasks 411. In one embodiment, the DTag production control signal isa part-demand-specific signal, which is derived from level planspublished on all pacemakers, including any additional finished gooddemand that is not supplied at some point by a pacemaker. Theconsolidated demand production control signal (of pacemaker and extrafinished good demand) is propagated to an upstream work center by one ormore engines 212. In addition, or as an alternative, one or more engines212 explodes a BOM of each demanded part to determine componentrequirements at each level of the BOM. The requirement being, forexample, the component part ID, quantity needed, and a start date whichis offset from the pacemaker start time or demand due date by aconservative estimate of the time needed to produce the component partand transport it to the demand source (pacemaker group or finished goodsinventory) by the start time/due date. In addition, one or more engines212 calculates the component requirements and consolidates theunfulfilled requirements into component part standard pack, assigns adue date from the earliest start/due date of any demand represented ineach standard pack, and allocates all started and/or full kanban ofdemanded components to the above demanded standard pack based on, forexample, highest priority, while accounting for phase-in/phase-outrequirements, other engineering changes, and the like.

In one embodiment, the DTag capability is turned on and off at the partlevel, along with other part-specific data, for example, via a Booleanflag indicating whether a part utilizes the DTag functionality. In oneembodiment, the default setting is N. In addition, when the DTag settingis at the part level, once the netted standard pack requirements aredetermined by one or more engines 212, a DTag comprising the componentpart ID and due date is generated for each standard pack requirement forthat part. In one embodiment, the DTags are visually represented in theoperator dashboard interface 400 for the producing work center. When,for example, more than one work center produces a part, allocation ofdemand to the relevant work center is defined in a part-work center datatable in a demand_proportion field, which must, for example, sum to 1across all part-work center combinations of each part.

In another embodiment, production control system 110 provides asite-wide Boolean flag, print_dtags, to allow DTag signals to be printedinto physical cards. If the setting is N, then the DTag printingcapability is disabled. However, if the setting is Y than the DTagprinting capability is enabled and a DTag printing button is visuallydisplayed in a production control system Master DB (a separateinteractive user interface in production control system 110 whichprovides an overview of the status of the entire production system)wherein the DTag printing button is visually grayed out if all DTagshave been printed, otherwise it is visually highlighted to indicate thata DTag printing workflow needs to be completed. In one embodiment, theDTag printing workflow is invoked when a new demand signal is receivedfrom one or more customers 130 a-130 n, for one or more parts requiringDTags. In addition, the dates for the DTags signals are maintained in acurrent and accurate state by production control system 110 anddisplayed in the operator dashboard interface 400.

In an embodiment, when the DTag setting is set to N for a part, at theinstant a standard pack is consumed and an empty kanban is released (tobe returned to the producing work center), production control system 110provides an empty kanban signal to authorize replenishment production ofthe part at the producing work center. In addition, if a DTag is notrequired for that part type then production control system 110 displaysa task in operator dashboard interface 400 of the part's producing workcenter corresponding to the empty kanban irrespective of any demand inthe system for that part.

In another embodiment, when the DTag setting is set to Y for a part, newtasks 411 for the part appear in operator dashboard interface 400 basedon standard pack requirements for the part from one or more engines 212rather than, for example, downstream consumption of the part generatingempty kanban. When, for example, the DTag setting is set to Y for apart, a separate column in job queue 410 indicates the number of DTagsneeded for its tasks since tasks will not show up in job queue 410without a DTag to generate them. In addition, if an unsatisfied DTagexists for a part, a new task 411 is created in operator dashboardinterface 400 for that part irrespective of the presence or absence ofan empty kanban for that part, and the task 411 is associated with theDTag until the task 411 is started, at which time the DTag is droppedfrom the production control system 110.

As an example only and not by way of limitation, production controlsystem 110 creates a DTag signal for each standard pack demanded. TheDTag is assigned to that standard pack, wherein the DTag is not definedat the work center trigger quantity for the part but at the standardpack level. That is, each task 411 on a work center 310 a-310 n isavailable to satisfy the number of DTags in the trigger (TRG) field 415,which is the number of standard packs in the trigger quantity. A newtask 411 for the trigger quantity of the part on the work center 310a-310 n is created in the operator dashboard interface 400 wheneverthere are unsatisfied DTags for the part, when other tasks 411 are fullyallocated to other DTags.

In addition, or as an alternative, when a task 411 is generated toaccommodate an unsatisfied DTag, the DTag is assigned to this task 411and the quantity required by the DTag is assigned to the DTag from thetask 411. In addition, production control system 110 assigns the balanceon hand (BOH) field 414 and assigns the days of cover (DOC) field 419 toeach task 411 of job queue 410. The part type and due date from the DTaghelp define the priority of the task 411. Any remaining quantity fromthe task 411 after satisfying current DTags is available to satisfy newDTags for the part, that is, as new DTags are created by one or moreengines 212. In addition, downstream consumption of the part providesempty kanban necessary to authorize tasks 411, but tasks 411 will alwaysbe present in the operator dashboard interface 400 sufficient to satisfyall demand for the part generated by the one or more engines 212 thatcannot be satisfied from full kanban (compete standard packs ininventory), wherein an empty kanban signal is not required for theappearance of such tasks in operator dashboard interface 400.

In one embodiment, the kanban (KB) field 420 b in operator dashboardinterface 400 indicates whether the required kanban are also present tocomplete the authorization. Production control system 110 does not allowthe initiation of production of tasks 411 that require more kanban thanthere are empty kanban for that part in the empty kanban queue at thework center 310 a-310 n. For example, in order to start production ofsuch tasks 411 the trigger quantity of the task 411 must be decreased toreduce required authorizations until available kanban are sufficient.The task 411 start date calculated by one or more engines 212 is used inthe prioritization of the tasks, along with demand type (build-to-order(BTO) or make-to-stock (MTS)) and setup requirements, so that, forexample, more urgent tasks are noted and completed first. In addition,once a standard pack requiring a DTag is partly consumed by a downstreamprocess, at the point where its kanban is considered “empty” andreleased to the upstream producing work center 310 a-310 n to authorizefurther production, the DTag for this standard pack is also removed ordeleted from production control system 110. This embodiment tends onaverage to slightly overestimate the demand for DTags by the quantity ofparts in partial kanban and in started but incomplete standard packs ofparent parts consuming the component part.

In one embodiment, when one or more engines 212 runs, it first deletesall DTags in the system, generates new DTags based on current demand,assigns DTags to any started and/or full kanban and unstarted tasks 411,creates new tasks 411 for remaining DTags, and then recalculates thepriorities of the unstarted tasks 411 in operator dashboard interface400 of the producing work center 310 a-310 n and sorts these unstartedtasks 411 in each work center 310 a-310 n accordingly. When, forexample, there are not enough DTags to assign to unstarted tasks 411,for example, when there has been a decrease in demand, one or moreengines 212 deletes remaining tasks 411 without any DTags from operatordashboard interface 400.

In one embodiment, the MTag production control signal represents amaterial authorization. That is, the MTag grants permission to havematerial (inventory) in the system based on available capacity (i.e., itis not part-specific). Production control system 110 stores two tables,which define the MTag static data separately from the MTag dynamic data,associated with one or more entities 120 a-120 n and/or one or morecustomers 130 a-130 n, in database 220. In addition, production controlsystem 110 utilizes these two tables in the production environment topopulate MTags in operator dashboard interface 400. In one embodiment,the first MTag Type table comprises static data including the followingfields, as shown below in Table 1.

TABLE 1 Field Name Type Default Description card_name ID required Uniquename for the MTag, indicating the relevant work center combinationdescription String null Description of MTag, detailing the relevant workcenter combination consuming_wc List required downstream work center inMTag work center pair producing_wc List required upstream work center inMTag work center pair start_date List Today First date card is active.List of dates includes today from production control system SiteParameter table and any week_start_day (Generally Sunday or Monday,populated in the production control system Site Parameter table).end_date List INF First date card is inactive. List of dates includesINF and any week_start_day (Generally Sunday or Monday, populated in theproduction control system Site Parameter table).

As shown above, table 1 requires one or more entries (rows) for eachMTag. Each entry defines the consuming work center in consuming_wc andthe producing work center in producing_wc, wherein each is populatedfrom a list of work centers. The description field may be optionallypopulated and has “producing_wc to consuming_wc” as its default. Thestart_date and end_date fields may be populated with defaults thatenable the MTag definition indefinitely, but may also be populated withany date defining a weekly boundary (the day of the week, for exampleSunday, defined by the parameter week_start_day in production controlsystem Site Parameter table), if desired to enable the MTag only for aparticular period.

In another embodiment, the second MTag table (Table 2) is the MTag Sizetable, defining the loop size for each MTag specified in the MTag table,as well as the loop size of the CMTag, (the site-wide CONWIP MTag).CMTag is a special MTag with neither a consuming nor a producing workcenter defined, and which may always be defined in production controlsystem 110. The MTag Size table (Table 2) comprises dynamic loop sizedata including the following fields for each MTag in the MTag table, aswell as for the site-wide CMTag, as shown below in Table 2.

TABLE 2 Field Name Type Default Description card_name List N/A Providedfrom MTag data (or “CONWIP” for the CMTag entry) description FString N/AProvided from Description in MTag data (or “CONWIP authorization” forthe CMTag entry) max FInt N/A Maximum MTag value, calculated byproduction control system 110 use_max Y/N Y Should production controlsystem 110 use the max value for the quantity? Y effectively turns offMTag capability by making it non-constraining quantity Int > 0 Max Loopsize: the number of cards deployed in system. Max is unconstraining,indicating that the MTag is ineffective, or turned off. start_date DateToday First date quantity of card active. List of dates includesstart_date from the corresponding MTag definition in the MTag table andany following week_start_day (Generally Sunday or Monday, populated inproduction control system Site Parameter table) before the end_date.end_date Date INF Last date quantity of card active. Cannot be on orbefore the start_date above or after the end_date of the correspondingMTag definition in the MTag table.

In the above Table 2, use_max, quantity, and the start_date and end_datefields may be populated by the user of production control system 110.The use_max field indicates whether production control system 110 shoulduse the value in the max field in the quantity field. In one embodiment,the default for use_max is Y, which disables the MTag feature by makingit non-constraining. In this case, any value in the quantity field isignored. When MTags are enabled in production control system 110 thenthe use_max field is set to N and a value less than max is entered inthe quantity field, which may be a custom value. In addition, the maxfield may be populated with a very large value, or with a symbol forinfinity, for example, “INF.”

In addition, or as an alternative, production control system 110automatically calculates and displays a meaningful value for max. Forexample, for MTags (those with a producing_wc and consuming_wcpopulated) this max value may be the sum of the loop sizes of all of thecomponents supplied from producing_wc to consuming_wc and all of theloop sizes of all of the components produced at consuming_wc. That is,when production control system 110 automatically calculates the maxdefault setting, a reasonable constraining boundary is identified and acomparison as to how constraining to the production control system acustom entry for quantity will be. For example, any quantity less thanmax may potentially constrain production flow, and the smaller thecustom quantity value is in relation to the max value the more likelymaterial flow will be constrained. In one embodiment, if this feature isenabled, an additional enhancement may be provided to supportcalculating the quantity of MTags in the system as a proportion of themax value by allowing quantity entries >0 and <1, which yield thequantity of MTags in the production control system when multiplied bymax.

As discussed above, with respect to Tables 1 and 2, there may bemultiple entries for each MTag definition in order to allow for atime-phased control of the MTag behavior. However, there must at alltimes be exactly one MTag entry in each of Tables 1 and 2 that has astart_date of Today (the production control system 110 start date) andone MTag entry having an end_date of INF (for example, corresponding toeternity or to some date beyond the planning horizon). In oneembodiment, the MTag Size table (Table 2) is automatically populatedwith one row for each MTag defined in the MTag Type table, and oneadditional row to define the CMTag.

If, for example, a planner associated with one or more entities 120a-120 n wishes to enter multiple instances of a particular MTag (CMTag)configuration, the planner may change the start_date or end_date of anexisting entry to another weekly boundary (that being a date in theplanning calendar corresponding to the day of the week stored inweek_start_day). In this case, production control system 110automatically generates a new MTag (CMTag) entry for the remainingperiod for which there is no definition, populates the start_date andend_date appropriately, populates the use_max value with “N,” and leavesthe cursor in the quantity field for the next planner entry.

The interactive MTag tables may also allow a planner to modify entriesby adjusting the start_date or end_date to another weekly boundary suchthat the span between these dates is at least one week, in which caseproduction control system 110 may accordingly adjust the start_date orend_date of the period which is overlapped by the change. In addition,the planner may change the start_date of one entry to be the same as thestart_date of some earlier period, or may change the end_date of oneentry to be the same as the end_date of some later period. In eithercase, production control system 110 may automatically remove theoverlapped entries, and may also advise the user of the pending eventprior to executing it and request the approval of the planner to do so,only executing the event if the planner approves the action. The plannermay then generate any desired pattern, and any pattern generated by theplanner will exactly partition the planning horizon, such that MTagdefinitions do not overlap or contain gaps.

As an example only and not by way of limitation, production controlsystem 110 deploys the MTags via operator dashboard interface 400. Thenumber and types of MTags assigned to a produced part at a work center310 a-310 n is derived from the MTag definitions in MTag Tables 1 and 2,and from the relevant BOMs. In one embodiment, each MTag represents astandard pack of input parts consumed at consuming_wc. The number ofMTags given in the MTag quantity field in the MTag table for each typeof MTag may be distributed among numerous states (states 1-5) for thatMTag depending on the status of, for example, a production floor of oneor more entities 120 a-120 n, in the following order:

-   -   1. All tasks 411 that are currently started at consuming_wc but        are not yet released to the downstream work center or inventory        buffer, where each physical MTag is attached to a standard pack        of parts produced at consuming_wc.    -   2. In the input queue of consuming_wc, where any physical MTags        are attached to full or partial standard pack of consumed parts.    -   3. Finished standard packs at producing_wc, where MTags are        attached to standard packs of parts produced at producing_wc and        consumed at consumed_wc.    -   4. Started (and unfinished) tasks 411 at producing_wc, where        MTags are attached to standard packs of parts produced at        producing_wc and consumed at consumed_wc.    -   5. MTag queues at producing_wc, where MTags wait to be attached        to tasks as tasks are started.

In one embodiment, production control system 110 assigns MTags to eachproduced standard pack at a work center that is listed in theconsuming_wc field in the MTag table. When a new standard pack isstarted at consuming_wc, for each producing_wc/consuming_wc combination,the new standard pack produced at consuming_wc is assigned the MTagsthat were assigned to the component part standard packs supplied byproducing_wc that are consumed by the new standard pack. In oneembodiment, these MTag quantities may be fractional, within productioncontrol system 110, depending on the quantity of items in a standardpack of the produced part, the quantity of items in a standard pack ofthe consumed part, and the quantity of consumed item consumed per unitof produced item in the BOM.

In another embodiment, in a physical deployment of the MTags, thephysical MTag may be attached to a standard pack of parts produced atconsuming_wc that consumes the last component of the consumed partstandard pack to which the MTag was previously attached. In such caseswhen the standard packs are completed at consuming_wc they are releasedto the downstream work center or inventory buffer in the order in whichthey were started. Otherwise, the number of MTags present at theconsuming_wc may not properly reflect the total quantities of theconsumed parts which are present at the consuming_wc. In such cases, alarger number of MTags may be required for adequate production flow atconsuming_wc, and the control over the component inventories atconsuming_wc may not be as precise.

In one embodiment, when production control system 110 identifies that acompleted standard pack leaves an MTag consuming_wc, production controlsystem 110 releases the MTags assigned to that standard pack back to,for example, states 2 through 5 above, first to state 2, then to state3, then to state 4, then to state 5. If, for example, the productionfloor of one or more entities 120 a-120 n is executing and reportingproduction and inventory movements correctly, released MTags may only bemoved from 1 to 5, since 2 and 3 may already be saturated with MTags.

In one embodiment, an MTag filter 418 is visually illustrated as anoption in operator dashboard interface 400 and filters out tasks 411requiring MTags when, for example, there are no MTags available in theMTag Queue. If MTag filter 418 is turned on (visually checked), tasks411 may only appear in operator dashboard interface 400 if there are,for example, both sufficient kanban and MTags present in the respectivequeues. In such a state, all tasks 411 appearing in operator dashboardinterface 400 are fully authorized by MTag and kanban availability. Insuch an embodiment, the MTag (MT) field 420 c and kanban (KB) field 420b provide no additional information and therefore need not be visuallyrepresented. MTag filter 418 eliminates visual clutter from operatordashboard interface 400 when kanban loop sizes are significantly higherthan MTag availability.

In addition, once MTags are released at consuming_wc, normally to, forexample, state 5 above, which is the MTag Queue of producing_wc, ifadditional tasks are available in the producing_wc but are not visuallydisplayed since MTag filter 418 is turned on, implying there are emptykanban in the Kanban Queue that have generated such tasks, thenproduction control system 110 visually displays all tasks that are nowfully authorizable in their MTag and kanban requirements. MTags bythemselves, without corresponding empty kanban, may not generate newtasks 411 since the MTags are not part-specific.

In one embodiment, the kanban and MTag signals are not actually assignedto task 411 when the task is created, but the signals remain in theirrespective queues until production of task 411 is initiated. A task maynot be initiated until it is authorized, and a task may not beauthorized until there are at least as many kanban for that part in thekanban queue as the trigger quantity, and at least as many MTags in theMTag Queue, having their consuming work centers defined as theconsuming_wc in the MTag, as the trigger quantity. Once an authorizedtask is initiated, the number of empty kanban for the produced part ofthe task in the kanban queue, and MTags in the MTag Queue having aconsuming_wc that consumes the part, are both reduced by the triggerquantity of the started task. If, for example, there are multiple typesof MTags in the MTag Queue with different consuming_wc entries that bothconsume the same item, indicating there are multiple MTag destinationsrequesting the item from the work center, production control system 110assigns the MTag type with the largest percentage of its MTags in MTagQueue, presuming that this measure indicates which producing work centersupplying MTags is most in need of component parts.

In one embodiment, with respect to the CMTag, at least one CONWIP entrymust always be present in the MTag Size table (Table 2) with a genericCMTag card_name of, for example, “CONWIP.” The default value for the maxfield of this CMTag entry may be infinity, or some extremely largenumber, for example, one trillion. However, production control system110 may populate this default value with a more meaningful value, whichis a more reasonable boundary condition defining when the CONWIPconstraint may become effective.

In another embodiment, production control system 110 provides anadditional CMTag field in a production control system part data, withdefault=Y. Production control system 110 stores and accesses productioncontrol system part data in database 220, in, for example, a table. Bydefault, production control system 110 turns on CMTags for all stage 1parts when CMTags become constraining, and thereby may begin toconstrain production of all stage 1 parts. If, for example, productioncontrol system 110 implements CONWIP on a subset of the stage 1 parts,the CMTag field is set to N in the production control system part datafor those stage 1 parts that are not to be constrained by CONWIP. Inaddition, or as an alternative, the CMTag field may be ignored for allparts that are not produced at stage 1 work center 310 a, as determinedby the BOM and Part-work center data.

In one embodiment, a reasonable boundary condition for the CMTag maxfield is the total quantity of all stage 1 produced parts having CMTag=Yin the production control system part data present in the productioncontrol system if all of the kanban in the production control systemwere full. This quantity is the sum of the products of the loop sizesall of the kanban in the system with their respective consumedquantities of the CMTag components anywhere in their BOM structure,determined via an explosion of the relevant BOM structures in theproduction control system BOM table. If, for example, the CMTag quantityfield is set below this max value and use_max=N, then CMTags begin toconstrain production. Any quantity values higher than max mayeffectively disable CMTag behavior when use_max=N, such that productionis never constrained by CMTags. When calculated by production controlsystem 110, this max value is automatically updated by productioncontrol system 110 whenever kanban loop sizes or finished good inventorytargets are updated, and is, for example, the largest such value at anypoint between the start_date and end_date for that entry in the MTagSize table (Table 2).

In another embodiment, the site-wide CMTag operates differently and isconfigured differently than the work center-specific MTags. For example,when production control system 110 enables CONWIP (CMTag quantitysetting lower than max in current time period and use_max=N), a CMTag isrequired by production control system 110 to authorize production of aCMTag part (any part having CMTag=Y in part data) at stage 1 work center310 a (e.g., a work center consuming only raw or procured materials). Inaddition, a CMTag is never required by any other type of task (since anyother task in production control system 110 will be consuming acomponent that has at least 1 CMTag assigned to it). When use_max=Nduring the current time period, any CMTag quantity setting lower thanthe max value during the current time period causes the operatordashboard interface 400 of every stage 1 work center 310 a which mayproduce a stage 1 CMTag part to visually display a CONWIP (CW) field 420d and a CONWIP button 434.

In one embodiment, CMTags are deployed at stage 1 work center 310 a viaa CMTag Queue. For each task 411 requiring CMTags in job queue 410 ofstage 1 work center 310 a, the CONWIP (CW) field 420 d displays thenumber of CMTags needed for authorization of the task in addition to thenumber of CMTags already present in the CMTag Queue at work center 310a.

In an embodiment, when CMTags are constraining material flow, stage 1work center 310 a is often starved of empty CMTags and places a CMTagrequest to one or more engines 212 that manage the distribution of emptyCMTags among the stage 1 work center 310 a when CMTags are released fromfinished good inventory (which is when a finished goods standard pack isshipped from the finished goods inventory system). To enable this CONWIPrequest and acquisition workflow when CMTags are in effect at a stage 1work center 310 a, an additional field 435 is visually displayed in theoperator dashboard interface 400 that indicates the number of CMTagsrepresented in unfulfilled CONWIP requests already made by other WorkCenters

The value in field 435 provides a visual indication of how long a waitmay be until a new CONWIP request is fulfilled. For example, a value of0 in the CONWIP (CW) field 420 b means that there are no unfulfilledCONWIP requests in the system, and that selecting the CONWIP buttongenerates a new CONWIP request that would be satisfied by before anyother work center's CONWIP request, such that the work center willreceive all CMTags that become available until the new CONWIP request isfulfilled. If, for example, field 435 is highlighted, the valueindicates that an open CONWIP request has been made and the visuallydisplayed value is the number of CMTags required to fulfill earlierCONWIP requests made by other work centers, which were made before thecurrent CONWIP request by the current work center.

In one embodiment, a check mark in CONWIP (CW) field 420 b visuallyindicates that there are sufficient CMTags available in the CMTag Queueof the work center to authorize production of the task. The CMTags inthe CMTag Queue are available to authorize any task 411 requiring CMTagsfor authorization; the CMTags are not assigned to tasks 411 requiringthem until tasks 411 are started, and so all CMTags at the work centerare available to all unstarted tasks at the work center to authorizewhichever task 411 is started. If, for example, the number of CMTagsavailable in the CMTag queue at stage 1 work center 310 a isinsufficient for a particular task 411, the remaining required quantityof additional CMTags needed to authorize task 411 may be displayed inCONWIP (CW) field 420 b for that task, and may also be requested by oneor more engines 212.

As an example only and not by way of limitation, one or more engines 212enables automatic distribution of CMTags across stage 1 work center 310a based on CMTag requests and task priorities. In doing so, productioncontrol system 110 defines a free CMTag as a CMTag that is not assignedto a started (or finished) task or to a work center to satisfy a CONWIPrequest. Remaining CMTags are assigned, either to stage 1 work center310 a or to parts produced at stage 1 work center 310 a. Assigned CMTagsbecome free when finished goods containing the relevant stage 1 producedparts are shipped from one or more entities 120 a-120 n, in which casethe number of CMTags consumed by the finished good item in its ordertree are released to the one or more engines 212. CMTags are alsoreleased to one or more engines 212 when the respective work centerstarts a task that requires fewer CMTags than the quantity assigned tothe work center, in which case the remaining CMTags assigned to the workcenter are released to one or more engines 212. Each shipped finishedgood component releases one CMTag for each unit of a CMTag part itcomprises.

In addition, when the CMTags are activated (CONWIP entry quantity<maxand use_max=N in MTag Size table (Table 2) in MTag definition effectivein current period). One or more engines 212 perform the CONWIPassignment workflow (discussed in more detail below) on a predeterminedtime basis, such as, for example, every 30 seconds, 1 minute, or anyother predetermined basis.

In order to further explain the operation of the CONWIP assignmentworkflow, an example is now given. In the following example, each workcenter 310 a-310 n producing a CMTag part (even theoretically, based onthe BOMs of the parts assigned to the work center for production, evenif there is currently no demand for the part) CONWIP button 434 may bepresent in the particular work center's operator dashboard interface400. CONWIP button 434 may be grayed out unless the selected task in jobqueue 410 is CMTag infeasible due to lack of CMTag availability at thework center, in which case there are insufficient CMTags available inthe CMTag Queue at the work center to authorize the selected task due toinsufficient free CMTags in the system. In this case, when the selectedtask is CMTag-infeasible, the CONWIP button 434 is visually highlightedin the operator dashboard interface 400.

A different task 411 may be selected, such as a task that is CMTagfeasible or one that does not require CMTags. In addition, a CONWIPrequest may be requested which opens a request to one or more engines212 for the standard pack quantity times the trigger quantity of theselected task. Any other task with sufficient CMTags available or a taskthat does not need CMTags may then be started, wherein the START button431 is visually highlighted in order to initiate production. If,however, another task 411 is selected that has insufficient CMTagsduring an open CONWIP request then CONWIP button 434 is visuallyhighlighted, only if the selected task needs more CMTags than what hasalready been requested from one or more engines 212. If CONWIP button434 is then selected, the earlier unsatisfied CONWIP request iscancelled and a new CONWIP request is submitted to one or more engines212 for the total quantity needed for the selected task and placed lastin the queue of open CONWIP requests in one or more engines 212. In thismanner, the CONWIP assignment workflow only permits one open CONWIPrequest in one or more engines 212 from any one work center at any onetime.

In addition, or as an alternative, in fulfilling CONWIP requests, one ormore engines 212 assign the requested quantity of CMTags to the workcenter of the CONWIP request that has been open the longest (a FIFOassignment), or if there isn't enough to satisfy the request, allremaining CMTags, in which case one or more engines 212 tries tocomplete this last unfulfilled request first in the subsequent CONWIPassignment workflow. The CONWIP button is grayed out in the operatordashboard interface 400 when one or more engines 212 satisfy the CONWIPrequest. All CMTags assigned to the work center in fulfillment of aCONWIP request remain assigned to the work center until the next task411 is started on that work center. A task 411 that is authorizable maybe started whenever no task is currently running on the work center. Ifa task 411 is started requiring CMTags then the CMTags required by thattask are assigned to the task from the CMTags available at the workcenter, and these CMTags remain assigned to the units of material in thestandard pack until finished good items fed by the task 411 are shippedfrom one or more entities 120 a-120 n. Any remaining CMTags assigned tothe work center are then released to one or more engines 212 as freeCMTags and are available for redistribution by one or more engines 212in the next CONWIP assignment workflow. These released CMTags remain inthe CMTag Queue of the work center until they are recalled by one ormore engines 212, and while in the CMTag Queue are available toauthorize further production at the work center.

In another embodiment and to further explain the operation of operatordashboard interface 400, an example is now given. In the followingexample, job queue 410 displays a list of all tasks currently planned ateach work center 310 a-310 n and provides visibility concerning thestatus of each task 411. As an example only and not by way oflimitation, operator dashboard interface 400 visually displays seventasks 411 in job queue 410 (although scroll bar 421 indicates thepresence of many other lower-priority tasks 411 in the queue, notshown). Although only seven tasks 411 are visually shown in FIG. 4,embodiments contemplate (as indicated by the scroll bar 421) any numberof tasks 411, according to particular needs.

In one embodiment, tasks 411 are sorted by the priority (P) fields 413such that, for example, the highest priority tasks (i.e., with smallerpriority values) appear at the bottom of job queue 410, near productionhistory 412 (tasks in the bottom portion of operator dashboard interface400). Although a particular priority is shown and described, anysuitable sorting or prioritization may be applied to tasks 411,according to particular needs.

In another embodiment, production control signal types 420 a-d of jobqueue 410 indicate whether or not each task 411 comprises theappropriate authorizations in order to authorize production. If not,production control signal types 420 a-d indicate how many additionalsignals of each relevant production control signal types 420 a-d arerequired to authorize the task. For example, tasks 411 having therequired authorization production control signals available to authorizeproduction provide a visual indication of a check mark in the respectivefields of the particular production control signal types 420 a-d. Inaddition, tasks 411 that do not have the required authorizations of aparticular production control signal type 420 a-d visually indicate inthe respective fields how many additional authorization productioncontrol signals of that type each task 411 requires in order toauthorize production (i.e., 2, 3, 4, etc.).

In an embodiment, trigger (TRG) field 415 displays a trigger value whenthe required number of kanban for each task 411 in job queue 410 exceedsa predetermined value, such as for example, one. The trigger value isthe number of kanban required for each part associated with each task411 to authorize production.

In another embodiment, production control system 110 displays the MTag(MT) field 423 when any MTags exist which have the particular workcenter 310 a-310 n as the producing work center 310 a-310 n. Any partsproduced on the producing work center 310 a-310 n and consumed on theconsumed work center 310 a-310 n of such an MTag will populate the MTag(MT) field 423 on the producing work center 310 a-310 n. However, if atask 411 does not require a production control signal type 420 a-d thenthe MTag (MT) field 423 remains blank for the respective field. Inaddition, unselected tasks 411 that are ready (i.e., fully authorizedfor all required production control signal types 420 a-d other thanCONWIP), are visually represented by highlighting in, for example, adifferent color and/or font type. In addition, the selected task 411 isvisually highlighted, in for example, a different color and/or fonttype, whether it is fully authorized for production or not. Although aparticular visual representation of highlighting is described,embodiments contemplate any suitable highlighting in color, text coloror style of font of the text, such that the visual representation of thedata may be visually highlighted, according to particular needs.

In an embodiment, production of a ready task 411 in job queue 410 isinitiated with sufficient CMTags, one of the highlighted tasks isselected (if the desired task is not already visually highlighted in adifferent manner, which is by default the bottom task in the sorted listwhen no tasks are currently running on the work center 310 a-310 n).This action visually grays out START button 431, moves the selected task411 into the production history 412 of operator dashboard interface 400and visually highlights PAUSE button 432 and DONE button 433. When task411 is finished, the operator may select the DONE button 433, or theproduction control system may automatically select DONE button 433 uponcompletion of the task, at which time the DONE button 433 may bevisually grayed out, which completes the task's production history 412information, and the last unstarted task in job queue 410 and STARTbutton 431 may then be visually highlighted. As discussed above,although a particular visual highlighting is shown and described, datamay be highlighted according to any suitable needs.

Modifications, additions or omissions may be made to operator dashboardinterface 400 without departing from the scope of the invention. As anexample and not by way of limitation, operator dashboard interface 400may have more, fewer, or other graphical elements. Moreover, theoperation of operator dashboard interface 400 may be performed by more,fewer, or other graphical elements, arranged in any suitable manner,according to particular needs.

FIG. 5 illustrates an exemplary method 500 for performing a CONWIPassignment workflow. The method begins at step 502, when the CMTags areactivated (CONWIP entry quantity<max and use_max=N in MTag Size table(Table 2) for an MTag definition effective in current period). Asdiscussed above, one or more engines 212 perform the CONWIP assignmentworkflow on a predetermined time basis.

At step 504, one or more engines 212 determines if there is an open(unsatisfied) CONWIP request from a stage 1 work center 310 a. If thereare open (unsatisfied) CONWIP requests, the method proceeds to step 506,otherwise, the method proceeds to step 510.

At step 506, one or more engines 212 recalls any free CMTags, inquantities sufficient to satisfy open CONWIP requests, and assignssufficient free CMTags to each stage 1 work center 310 a generating aCONWIP request, in, for example, a First-in First-out (FIFO) manner,satisfying older CONWIP requests first. Next at step 508, one or moreengines 212 close satisfied CONWIP requests, that is, close requestswhere one or more engines 212 has assigned to the requesting work centerthe requested quantity of CMTags in that work center's open CONWIPrequest.

At step 510, one or more engines 212 prioritize all unstarted CMTagtasks 411 planned on any stage 1 work center 310 a which areauthorizable apart from the CMTag (those tasks which have sufficientauthorization and inventory otherwise) on a common priority schemecomparable to that used in operator dashboard interface 400 at eachstage 1 work center 310 a. Next, at step 512, one or more engines 212allocate remaining free CMTags to work centers to satisfy tasks 411 byhighest priority, update the relevant values in the CONWIP (CW) field420 d of job queue 410, but do not assign these free CMTags to the workcenter. (The CMTags are still considered free, and will be recalled fromthe work center to fulfill open CONWIP requests as needed, first fromwork centers with the lowest priority tasks. Until such time as freeCMTags are recalled by one or more engines 212, they remain available toauthorize any task at that work center.)

Next at step 514, one or more engines 212 determine if any free CMTagsremain. If there are any free CMTags, the method proceeds to step 516,otherwise, the method ends. At step 516, one or more engines 212 makesthe remaining free CMTags available to stage 1 work center 310 a withthe largest sum of the values in the CONWIP (CW) field 420 d and updatesthe CONWIP (CW) fields 520 d values accordingly. Once the CONWIP (CW)fields 520 d are updated, the method ends. In addition, although, FIG. 5illustrates one embodiment of a method for performing a CONWIPassignment workflow, various changes may be made to method 500 withoutdeparting from the scope of embodiments of the present invention.

FIG. 6 illustrates an exemplary method 600 for providing productioncontrol authorization signals in the production environment of entity120 a. The method begins at step 602, where a demand signal is receivedfrom one or more customers 130 a-130 n at production control system 110.The demand signal is propagated into N+1 DTag signals, 1 for each of Nwork centers 310 a-310 n and 1 for the final finished goods buffer. Atstep 604, a distinct DTag is produced for each standard pack of eachpart ID required at every work center, after rounding up the grossrequirement of each part to the nearest standard pack. In addition,dependent component material requirements are propagated to upstreamwork centers based on, for example, lead times, BOMs, yield andengineering change notice (ECN).

In one embodiment, production control system 110 replaces all existingDTags and re-propagates the entire DTag signal each time the demandsignal is updated. In another embodiment, production control system 110provides a net change type of workflow wherein only the new demandsignals are propagated. In either embodiment, the DTag is deleted ordestroyed once it has succeeded in authorizing production of a standardpack and production has been initiated. In addition or as analternative, if that standard pack is not completed or is scrapped,other means in the production control system may be initiated to make upthe production, as in the use of safety stock, etc, such that the DTagneed not be recreated.

At step 606, Synchronization Station U_(i), shown in FIG. 3 coordinatesthe timely aggregation of multiple production authorization signals toensure that all authorizations required by task 411 are present beforeproduction is initiated. Each U_(i) may have up to 4 productionauthorizations, a DTag which is satisfied (destroyed) when productionbegins (d_(i)), kanban which is a standard production authorization(k_(i)), an MTag for each MTag having WC_(i) in producer list and wc, inconsumer list (_(i)m_(j)), and a CMTag at MP₁ MTag loopsize with nullproducer/consumer work centers (m).

At step 608, when the first item in a standard pack of a part P_(i)produced at MP_(i) is consumed by part P_(i+1) produced at MP_(i+1), thekanban k_(i) is returned to kanban queuing station K_(i). At step 610,MTags _(i)m_(j) return to queuing station M_(i) when part P_(i+1) isreleased to MP_(i+2). At step 612, CONWIP MTags m are released only whenfinished good parts containing them are shipped to one or more customers130 a-130 n. Once the CONWIP MTags m are released, the method ends. Inaddition, although, FIG. 6 illustrates one embodiment of a method forproviding production control authorization signals in a productionenvironment, various changes may be made to method 600 without departingfrom the scope of embodiments of the present invention.

FIG. 7 illustrates an exemplary method 700 for providing productioncontrol signals in the production environment of entity 120 a. At step702, production control system 110 determines if a part requires a DTag.If a part requires a DTag, the method proceeds to step 704, otherwise,the method proceeds to step 714. At step 704, production control system110 posts a new task 411 for that part in operator dashboard interface400 of the producing work center as soon as a DTag for the part ispresent in the production control system, which cannot be satisfied bythe tasks for that part currently created in job queue 410 (since theymay be fully assigned to other DTags). At step 706, production controlsystem 110 creates a task 411, even if no other signal required forauthorization is present (MTag, CMTag and/or kanban).

At step 708, production control system 110 displays an additional fieldin job queue 410 for each additional production authorization signalrequired by any task 411 in job queue 410. At step 710, productioncontrol system 110 determines if any task 411 in work centers 310 a-310n requires an MTag and if MTag filter 418 is off (unchecked). If an MTagis required and MTag filter 418 is off, the method proceeds to step 712,otherwise, the method proceeds to step 714. At step 712, productioncontrol system 110 displays the MTag (MT) fields 520 c and Kanban (KB)fields 520 b in operator dashboard interface 400. In addition, if CONWIPis enabled for any part produced at a stage 1 work center 310 a then theCONWIP (CW) field 420 d may be displayed in operator dashboard interface400 of work center 310 a.

At step 714, production control system 110 determines if the partrequires a work center-specific MTag. If a part requires a workcenter-specific MTag, the method proceeds to step 716, otherwise, themethod proceeds to step 722. At step 716, production control system 110determines if MTag filter 418 is off. If MTag filter 418 is off, themethod proceeds to step 718, otherwise, the method proceeds to step 720.

At step 718, production control system 110 posts a task 411 for thatpart in operator dashboard interface 400 of the producing work center assoon as an empty kanban appears for that part. At step 720, productioncontrol system 110 visually displays the task only when there aresufficient MTags and kanban available to authorize production of astandard pack the part, which may be less than trigger quantity.

At step 722, production control system 110 visually displays a task 411for the part in operator dashboard interface 400 of the producing workcenter as soon as an empty kanban signal is produced at a downstreamwork center and the execution of all of the tasks for the part currentlyopen on the work center would not consume all of the empty kanban forthat part.

At step 724, production control system 110 determines if tasks 411 areconsidered ready and if all production authorizations required for task411 except the CMTag are available in their respective queues at thework center. When tasks 411 are considered ready, the method proceeds tostep 726, otherwise, the method continues to determine whether tasks 411are ready.

At step 726, production control system 110 visually highlights the readytasks 411, in for example, alternating lighter and darker shades ofhighlighting color. In addition, or as an alternative, productioncontrol system 110 visually highlights the START button 431 when thetask is selected so that the task on the work center can be started ifthe task: does not require the CMTag, or requires the CMTag and the workcenter has sufficient CMTag available to authorize the task. Inaddition, production control system 110 visually highlights the CONWIP(CONWIP) button 434 if they require CMTags and there are insufficientCMTags available in the CMTag Queue of the work center. Otherwise thetask remains un-highlighted and the task is not able to be selected.

Once ready tasks 411 are selected, the method ends. In addition,although, FIG. 7 illustrates one embodiment of a method for providingproduction control signals in the production environment, variouschanges may be made to method 700 without departing from the scope ofembodiments of the present invention.

In accordance with the principles of embodiments, the DTag, MTag (andCMTag) and kanban production authorization control signals may beinvoked in any of various combinations in order to control productionwithin one or more entities 120 a-120 n, as needed. As an example onlyand not by way of limitation, DTags may be utilized in environmentswhere demand is volatile and/or the BOM is complex and/or the amount oftime required to produce finished goods from raw materials issignificant. Similarly, MTags may be utilized to manage production flowthrough intermediate capacity constrained work centers to minimizeexcess inventory and provide for smooth production flow. Similarly,CMTags may be utilized in environments where product mix is volatileand/or the number of component parts used in production is significant.Similarly, kanban may be utilized in environments where productionconstraints are in the latter stages of production, and/or whereproduction processes and/or component supplies are unreliable and/or inenvironments where is it impractical to publish a manufacturing plan inan accurate and timely manner.

Reference in the foregoing specification to “one embodiment”, “anembodiment”, or “another embodiment” means that a particular feature,structure, or characteristic described in connection with the embodimentis included in at least one embodiment of the invention. The appearancesof the phrase “in one embodiment” in various places in the specificationare not necessarily all referring to the same embodiment.

While the exemplary embodiments have been shown and described, it willbe understood that various changes and modifications to the foregoingembodiments may become apparent to those skilled in the art withoutdeparting from the spirit and scope of the present invention.

What is claimed is:
 1. A system, comprising: a database storingproduction control data associated with one or more entities; aproduction control system coupled with the database and configured tomodel a production control framework of the one or more entities, theproduction control system comprising: one or more work centersauthorizing one or more tasks for one or more parts; one or more demandauthorization signals generated when a demand is received at the one ormore entities; one or more work center-specific material authorizationsignals; one or more site-specific material authorization signals; oneor more pull-based production control signals; and one or moremanufacturing processes that produce one or more finished parts usingthe one or more parts.
 2. The system of claim 1, wherein each of the oneor more work centers comprise: a demand queuing stage; a part-specificqueueing stage; a material queueing stage; and an output buffer stage.3. The system of claim 1, wherein a work center of the one or more workcenters comprise an output buffer stage comprising a target inventoryset to a sum of output buffer capacity and output buffer production leadtime requirements.
 4. The system of claim 1, wherein at least one of theone or more work center-specific material authorization signalsspecifies a consuming work center and a producing work center andrepresents the maximum amount of inventory present at a destination workcenter.
 5. The system of claim 1, wherein the one or more work centersauthorize the one or more tasks when at least one of the one or moredemand authorization signals is present in the production control systemand currently authorized tasks do not satisfy a demand.
 6. The system ofclaim 5, wherein: the one or more work centers authorize the one or moretasks when the one or more finished parts require at least one of theone or more work center-specific material authorization signals, awork-center specific material authorization signal filter isdeactivated, and at least one of the one or more pull-based productioncontrol signals is generated for the one or more finished parts; orauthorize the one or more tasks when the one or more finished partsrequire at least one of the one or more work center-specific materialauthorization signals, the work-center specific material authorizationsignal filter is activated, a number of the one or more workcenter-specific material authorization signals are available and thenumber of the one or more work-specific material authorization signalsis greater than a predetermined number of work-center specific materialauthorization signals required for a pack of the one or more finishedparts, and at least one of the one or more pull-based production controlsignals is generated for the one or more finished parts.
 7. The systemof claim 6, wherein the one or more work centers authorize the one ormore tasks when none of the one or more demand authorization signals norany of the one or more of the work center-specific materialauthorization signals have been associated with the one or more finishedparts and when at least one of the one or more pull-based productioncontrol signals is generated for the one or more finished parts andcompletion of all of the currently authorized tasks for the one or morefinished parts would not use all of the one or more pull-basedproduction control signals generated for the one or more finished parts.8. The system of claim 1, further comprising: one or more stage one workcenters authorizing one or more tasks for one or more initial partsassociated with a number of one or more of the site-specific materialauthorization signals at the one or more stage one work centers whereinthe one or more finished parts comprise approximately an equal number ofthe one or more initial parts when the number of one or more of thesite-specific material authorization signals associated with the one ormore initial parts equals a standard pack quantity multiplied by atrigger quantity.
 9. A method, comprising: storing, by a computer,production control data associated with one or more entities in adatabase; authorizing, by the computer, one or more tasks for one ormore parts at one or more work centers; generating, by the computer, oneor more demand authorization signals generated when a demand is receivedat the one or more entities, one or more work center-specific materialauthorization signals, one or more site-specific material authorizationsignals, and one or more pull-based production control signals; andproducing, by the computer, one or more finished parts using the one ormore parts at one or more manufacturing processes.
 10. The method ofclaim 9, wherein each of the one or more work centers comprise: a demandqueuing stage; a part-specific queueing stage; a material queueingstage; and an output buffer stage.
 11. The method of claim 9, wherein awork center of the one or more work centers comprise an output bufferstage comprising a target inventory set to a sum of output buffercapacity and output buffer production lead time requirements.
 12. Themethod of claim 9, further comprising: defining at least one of the oneor more work center-specific material authorization signals to specify aconsuming work center and a producing work center and to represent themaximum amount of inventory present at a destination work center. 13.The method of claim 9, wherein the one or more work centers authorizethe one or more tasks when at least one of the one or more demandauthorization signals is present in the production control system andcurrently authorized tasks do not satisfy a demand.
 14. The method ofclaim 13, wherein: the one or more work centers authorize the one ormore tasks when the one or more finished parts require at least one ofthe one or more work center-specific material authorization signals, awork-center specific material authorization signal filter isdeactivated, and at least one of the one or more pull-based productioncontrol signals is generated for the one or more finished parts; orauthorize the one or more tasks when the one or more finished partsrequire at least one of the one or more work center-specific materialauthorization signals, the work-center specific material authorizationsignal filter is activated, a sufficient number of the one or more workcenter-specific material authorization signals are available and thenumber of the one or more work-specific material authorization signalsis greater than a predetermined number of work-center specific materialauthorization signals required for a pack of the one or more finishedparts, and at least one of the one or more pull-based production controlsignals is generated for the one or more finished parts.
 15. The methodof claim 14, wherein the one or more work centers authorize the one ormore tasks when none of the one or more demand authorization signals norany of the one or more of the work center-specific materialauthorization signals have been associated with the one or more finishedparts and when at least one of the one or more pull-based productioncontrol signals is generated for the one or more finished parts andcompletion of all of the currently authorized tasks for the one or morefinished parts would not use all of the one or more pull-basedproduction control signals generated for the one or more finished parts.16. The method of claim 9, further comprising: authorizing, by thecomputer, one or more tasks for one or more initial parts associatedwith a number of one or more of the site-specific material authorizationsignals at one or more stage one work centers wherein the one or morefinished parts comprise approximately equal number of the one or moreinitial parts when the number of the one or more site-specific materialauthorization signals associated with the one or more initial partsequals a standard pack quantity multiplied by a trigger quantity.
 17. Anon-transitory computer-readable medium embodied with software whichwhen executed using one or more computers is configured to: storeproduction control data associated with one or more entities in adatabase; authorize one or more tasks for one or more parts at one ormore work centers; generate one or more demand authorization signalsgenerated when a demand is received at the one or more entities, one ormore work center-specific material authorization signals, one or moresite-specific material authorization signals, and one or more pull-basedproduction control signals; and produce one or more finished parts usingthe one or more parts at one or more manufacturing processes.
 18. Thenon-transitory computer-readable medium of claim 17, wherein each of theone or more work centers comprise: a demand queuing stage; apart-specific queueing stage; a material queueing stage; and an outputbuffer stage.
 19. The non-transitory computer-readable medium of claim17, wherein a work center of the one or more work centers comprise anoutput buffer stage comprising a target inventory set to a sum of outputbuffer capacity and output buffer production lead time requirements. 20.The non-transitory computer-readable medium of claim 17, furtherconfigured to: define at least one of the one or more workcenter-specific material authorization signals to specify a consumingwork center and a producing work center and to represent the maximumamount of inventory present at a destination work center.
 21. Thenon-transitory computer readable medium of claim 17, wherein the one ormore work centers authorize the one or more tasks when at least one ofthe one or more demand authorization signals is present in theproduction control system and currently authorized tasks do not satisfya demand.
 22. The non-transitory computer readable medium of claim 21,wherein: the one or more work centers authorize the one or more taskswhen the one or more finished parts require at least one of the one ormore work center-specific material authorization signals, a work-centerspecific material authorization signal filter is deactivated, and atleast one of the one or more pull-based production control signals isgenerated for the one or more finished parts; or authorize the one ormore tasks when the one or more finished parts require at least one ofthe one or more work center-specific material authorization signals, thework-center specific material authorization signal filter is activated,a number of the one or more work center-specific material authorizationsignals are available and the number of the one or more work-specificmaterial authorization signals is greater than a predetermined number ofwork-center specific material authorization signals required for a packof the one or more finished parts, and at least one of the one or morepull-based production control signals is generated for the one or morefinished parts.
 23. The non-transitory computer readable medium of claim22, wherein the one or more work centers authorize the one or more taskswhen none of the one or more demand authorization signals nor any of theone or more of the work center-specific material authorization signalshave been associated with the one or more finished parts and when atleast one of the one or more pull-based production control signals isgenerated for the one or more finished parts and completion of all ofthe currently authorized tasks for the one or more finished parts wouldnot use all of the one or more pull-based production control signalsgenerated for the one or more finished parts.
 24. The non-transitorycomputer readable medium of claim 17, further comprising: authorizingone or more tasks for one or more initial parts associated with a numberof one or more of the site-specific material authorization signals atone or more stage one work centers wherein the one or more finishedparts comprise approximately equal number of the one or more initialparts when the number of the one or more site-specific materialauthorization signals associated with the one or more initial partsequals a standard pack quantity multiplied by a trigger quantity.